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Фрагмент инструкции
Press F2 to choose the type of aid you are testing. The selections are AGC 50, LINEAR 50, LINEAR 60. • Choose LINEAR 60 for most linear aids. • Choose LINEAR 50 for high-gain aids. • Choose AGC for AGC aids. Note: If you are testing a digital aid, you should usually select AGC for this setting. However, ask the hearing aid manufacturer for guidance. 2. Press F3 to select the last frequency of the three frequency average used in the test sequence. See Section 2.4.1 for details. 3. Press F5 to turn the telecoil test off and on. The telecoil test requires the external telecoil board. 4. Press F6 to select the noise reduction used in the measurements. Automated Test Sequences63 5. Press F7 to select the battery type used in the measurements. 6. Press F8 to select whether or not you want to perform an equivalent input noise (EQIN also known as EIN) measurement. Note: The equivalent input noise measurement is difficult without a very quiet environment, especially with low gain aids. 7. Decide whether you want to test with or without the reference microphone. See Section 3.4.9 for instructions on the reference microphone. 4.3.2 Running the test sequence 1. Level the sound chamber, if necessary. See Section 3.2 for details. 2. Set up the aid for testing. See Section 4.2.1. 3. Close the sound chamber. 4. Press START/STOP when you are ready to begin the test. 5. If you turned on the telecoil test: a. Plug the external telecoil board into the external speaker jack on the back of the FP40. b. Set the aid to receive telecoil signals c. Position the aid and coupler on the telecoil board so that the TCOIL reading on the display is as large as possible. d. Press START/STOP to take the measurement. e. Return the aid and coupler assembly to the sound chamber, and put the aid back to microphone mode. f. Unplug the telecoil board. g. Press START/STOP to resume the test. 6. Wait for several tests to be run. For most linear aids, the analyzer will pause after performing several measurements in order for you to turn down the gain of the aid. 7. If the analyzer pauses, open the sound chamber and adjust the gain control of the aid until the HFA (or SPA) MEASURED gain matches the HFA (or SPA) TARGET gain to within 1 dB when the sound chamber is closed. 8. Press START/STOP to complete the test sequence. 4.3.3 Viewing the results See Figure 4.3.3 for an example of ANSI 87 results 1. SSPL90: Output measurement at 90 dB SPL 2. RESP50 (or 60): Response measurement at 50 (or 60) db SPL 3. NR: Noise reduction used in tests 4. SPA/HFA: Frequencies used for the three frequency average 64FONIX FP40 Portable Hearing Aid Analyzer 5. MAX: Maximum frequency response measured and the frequency at which it occurred 6. SPA/HFA SSPL90: Three frequency average of the OSPL90 curve 7. SPA/HFA FOG: Three frequency average of a full-on gain measurement at 50 (or 60) dB SPL 8. REF TEST GAIN: The measured reference test gain 9. EQ INP NOISE: Equivalent input noise 10. RESP LIMIT and F1 and F2: The response limit level and the two frequencies where the response curve crossed over this level 11. THD: The total harmonic distortion measurements 12. BATTERY: Battery current drain 13. I/O CURVE: Input/output measurement at 2000 Hz Figure 4.3.3—ANSI 87 results 4.4 ANSI S3.42-1992 The ANSI 92 test sequence is a series of tests designed for non-linear hearing aids. Although it is not used by manufacturers to label hearing aids, it can give you valuable information not present in the ANSI S3.22 labeling standard. ANSI 92 is only available if you have the Composite Option on your analyzer. ANSI 92 uses the Composite signal to run a family of frequency responses at different input levels. The Composite signal is critical for accurate testing of non-linear hearing aids because of a well- known effect associated with pure-tone sweeps known as “artificial blooming.” When a pure-tone sweep is presented to a non-linear hearing aid, the aid’s AGC circuits can sometimes react by inflating their gain at low frequencies. This can result in inaccurate frequency response curves. This artificial blooming of the low frequencies does not occur when a broadband signal, such as the Composite signal, is used. Automated Test Sequences65 4.4.1 Setting up for the test Follow the instructions found in Section 4.2.1 for instructions on setting up the aid for testing. To enter the ANSI 92 screen: 1. From the Main Coupler Screen, look at the FP40’s display above the F4 function key. If it says “AN92” , skip to step 6. 2. Press F1—Menu. 3. Use the AMPLITUDE and FREQUENCY knobs to select MAIN F4 under FUNCTION KEY DEFIN. 4. Press START/STOP to choose AN92. This will let you use the F4 function key to enter the ANSI 92 screen from the Main Coupler Screen. 5. Press F1 to return to the Main Coupler Screen. 6. Press F4 to enter the ANSI 92 screen. To change the ANSI 92 settings: 1. Press F2 to select the desired range of input levels for the frequency response curves. 2. Press F3 to select the sett...
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